Re: [PATCH 8/8] x86, mce, edac: call edac_mce_parse() once per a record

Borislav Petkov
2011-06-17T17:10:52Z

On Fri, Jun 17, 2011 at 04:50:48AM -0400, Hidetoshi Seto wrote:
> There is no reason to keep it in the cmpxchg loop.
> (The loop continues until mcelog acquires buffer to save the record)
>
> And use do-while for the loop here.
>
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

Good catch.

Reviewed-by: Borislav Petkov <borislav.petkov@amd.com>

> ---
> arch/x86/kernel/cpu/mcheck/mce.c | 26 +++++++++++++-------------
> 1 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index bc8a02c..f1d8ce1 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -148,21 +148,21 @@ void mce_log(struct mce *mce)
> /* Emit the trace record: */
> trace_mce_record(mce);
>
> + /*
> + * If edac_mce is enabled, it will check the error type and will
> + * process it, if it is a known error.
> + * Otherwise, the error will be sent through mcelog interface.
> + */
> + if (edac_mce_parse(mce))
> + return;
> +
> mce->finished = 0;
> wmb();
> - for (;;) {
> +
> + do {
> entry = rcu_dereference_check_mce(mcelog.next);
> for (;;) {
> /*
> - * If edac_mce is enabled, it will check the error type
> - * and will process it, if it is a known error.
> - * Otherwise, the error will be sent through mcelog
> - * interface
> - */
> - if (edac_mce_parse(mce))
> - return;
> -
> - /*
> * When the buffer fills up discard new entries.
> * Assume that the earlier errors are the more
> * interesting ones:
> @@ -181,10 +181,10 @@ void mce_log(struct mce *mce)
> }
> smp_rmb();
> next = entry + 1;
> - if (cmpxchg(&mcelog.next, entry, next) == entry)
> - break;
> - }
> + } while (cmpxchg(&mcelog.next, entry, next) != entry);
> +
> memcpy(mcelog.entry + entry, mce, sizeof(struct mce));
> +
> wmb();
> mcelog.entry[entry].finished = 1;
> wmb();
> --
> 1.7.1

Thanks.

--
Regards/Gruss,
Boris.

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